F-150 - "Check Engine" light issue

[mikemorvan]

'14, F-150, 5.0, 115,000 +/- miles. Check engine light came on a few weeks ago. Had spark plugs changed and coils in cylinder 2 & 8 replaced. Check engine light comes on again a couple of weeks later. Two catalytic converters replaced.

Now, when pulling a load in "two / haul" mode and i get up to or just over 70 mph, the check engine lights flickers on for a few seconds then goes off. Eventually the light comes on and stays on. Once i quit pulling a load, and drive it for awhile, around 50 miles, the light goes off and returns to normal.

Anyone have any thoughts before i get it checked out again. I hate being an automotive dummy.

[Kingfisher789]

What code does it set? Have you flushed injectors? Run some Techron fuel additive thru it

[mikemorvan]

I don't know what code it sets. Will run the Techron tomorrow.

[Buckshot-73]

Your Knuter valve is bad.

[oktx]

Son has 2014 f150 108,000 miles. His check engine light is on for the cats. Still runs fine, needs to get looked at.

[mikemorvan]

Your Knuter valve is bad.

On it. Thanks for the quick diagnosis.

[30-30]

Your Knuter valve is bad.

So that’s how it’s spelled.

[175gr7.62]

A $30 Bluetooth OBDII adapter and a $5 phone app will saves you tons of money and head scratching. I like Torque Pro.


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[mikemorvan]

Will check these out. Thanks.

[BigL]

A friend was having his check engine light flicker like that and it was his mass air flow sensor.

Get the cleaner spray and try cleaning it before replacing the part.

Btw I'm not an expert just passing on what his issue was. Actually just cleaned mine today because of the way it was idling and he had the spray handy. Didn't drive much today so can't say if it helped or not.

[Slicefixer]

A $30 Bluetooth OBDII adapter and a $5 phone app will saves you tons of money and head scratching. I like Torque Pro.


Sent from my iPhone using Tapatalk

This ....100%..... Amazing app..... Mines running on an old note phone ANYtime my engine is running.

Might well save you an engine or transmission....

[sailor]

Check your O2 sensor...…….

[Pedernal]

Hopefully this is still correct information. Most vehicles will have a log of the codes that have caused the service light to turn on. Many auto parts (like autozone) used to have a code reader handy and would get you the codes for no charge.

[Goldeneagle]

A friend was having his check engine light flicker like that and it was his mass air flow sensor.

Get the cleaner spray and try cleaning it before replacing the part.

Btw I'm not an expert just passing on what his issue was. Actually just cleaned mine today because of the way it was idling and he had the spray handy. Didn't drive much today so can't say if it helped or not.

MAF will make it do some weird things. I had a 2000 F150 getting all kinds of codes. Put a new MAF on it and everything was fine.

[pervis]

Id bet money its your mass air flow sensor being dirty or going out. My 150 pretty much did the same thing. Make sure to buy a oem mass air flow sensor if your gona replace it, not a ebay knock off. You get a knock off and not a genuine ford one and it ll make you wana pull your hair out w more codes than u can imagine.